Virgin Islands National Parkconservation area covering some three-fifths of the island of St. John in the United States Virgin Islands, West Indies. The park was established in 1956 and now also includes waters surrounding St. John (added in 1962) and most of Hassel Island (1978) in the harbour of Charlotte Amalie (on the island of St. Thomas). It covers a total area of 23 square miles (60 square km) of land and water. The park was designated a UNESCO International World Network Biosphere Reserve in 1983.

The original inhabitants, the agricultural Arawak Indians, left rock carvings. The Arawak were killed or pushed out by Caribs before Christopher Columbus arrived in 1493. Danish sugar plantations were established in the late 17th century, and permanent settlement began in the early 18th century. The abolition of slavery on the island in 1848 was a primary reason for the decline of sugar cultivation, which had ended by the time the United States purchased the Virgin Islands in 1917; the population dwindled and turned to subsistence farming.

The landscape consists of steep mountains, deep valleys, white-sand beaches, and coral reefs. Most of the tree cover was removed for sugarcane cultivation, but when the plantations were abandoned the land reverted to forest. The park is home to some 800 species of plants, many of them introduced, in a range of habitats from moist subtropical highlands to semiarid scrubland. Cactus and agave grow in the driest areas. Mangrove swamps along the shore and sea grass beds in shallow water provide food and protection for marine life. Orchids, hibiscuses, frangipani, bougainvilleas, palms, kapok trees, mangoes, and bay rum (prized for its scented oil) are common; sea grapes and manchineel (Hippomane mancinella) grow on the beaches. The park’s coral reefs support a wide variety of colourful fish and other marine life. More than 20 species of tropical birds, such as the ani and the bananaquit, nest on the island, and dozens of migrating species visit. Pelicans, frigate birds, and a variety of shorebirds are commonly seen along the beach, and endangered green and hawksbill sea turtles nest there. Lizards such as geckos, anoles, and iguanas are abundant. The only native land mammal is the bat; the mongoose was introduced from Europe to control rodents and has since eliminated or depleted populations of native birds and sea turtles by eating their eggs.

Sugar plantation ruins, including the 1718 Annaberg Sugar Mill, can be seen in the park. Water activities such as snorkeling (Trunk Bay has an underwater trail), scuba diving, sailing, windsurfing, and fishing are popular, and there are several hiking trails. Virgin Islands Coral Reef National Monument (2001) is adjacent to the northeastern and southern portions of the park. Buck Island Reef National Monument is off the island of St. Croix, about 40 miles (65 km) south.